Domestication
Some of the species cultivated by Indians for food are today considered undesirable weeds. Another name for marshelder is sumpweed; chenopods are derisively called pigweed, although one South American species with a more attractive name, quinoa, is a health food store favorite. The reason for the unattractive names of former American food plants is probably because they are the colonizers of disturbed soil, the first fast-growing weeds to spring up when a natural or man-made event, such as a fire, leaves a bare patch of soil.
The process of domestication of wild plants cannot be described with any precision. However, Bruce D. Smith and other scholars have pointed out that three of the domesticates (chenopods, I. annua, and C. pepo) were plants that thrived in disturbed soils in river valleys. In the aftermath of a flood, in which most of the old vegetation is killed by the high waters and bare patches of new, often very fertile, soil were created, these pioneer plants sprang up like magic, often growing in almost pure stands, but usually disappearing after a single season, as other vegetation pushed them out until the next flood.
Indians, probably women, learned early that the seeds of these three species were edible and easily harvested in quantity because they grew in dense stands. C. pepo was important also because the gourd could be made into a lightweight container that was useful to a seminomadic band. Chenopods have edible leaves, related to spinach and chard, that may have also been gathered and eaten by Indians. Chenopod seeds are starchy; marsh elder has a highly nutritious oily seed similar to sunflower seeds.
In gathering the seeds, the women undoubtedly dropped some in the sunny environment and disturbed soil of a settlement, and those seeds sprouted and thrived. Over time, women learned to sow the seeds and to clear the ground of any competitive vegetation. The seeds which germinated quickest (i.e. thinner seed coats) and the plants which grew fastest were the most likely to be tended, harvested, and replanted. Over time, first through a process of unconscious selection and, later, conscious selection, the domesticated weeds became more productive. The seeds of some species became substantially larger and/or their seed coats were less thick compared to the wild plants. Conversely, when Indians quit growing these plants, as they did later, their seeds reverted within a few years to the size they had been in the wild.
By about 500 BCE, seeds produced by six domesticated plants were an important part of the diet of Indians in the middle Mississippi River valley of the United States.
Read more about this topic: Eastern Agricultural Complex